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    <title>Document</title>
    <script>

        //
        var age = 30;

        if (age >= 60) {
            console.log("满足退休条件");
        } else if (age >= 55) {
            console.log("!-_-您好，别着急还有 " + (60 - age) + "年退休");
        } else {
            console.log("不行");
        }


        // if (false)
        //     console.log(11111);
        //     console.log(2222);

        // 非空  非0    非  null   undefined      -  true
        // null undefined 0     --false
        if (0) {
            console.log(1111)
        }


        let score = 9999;
        console.log("score ", score);
        if (Math.floor(score / 10) == 9 || Math.floor(score / 10) == 10) {
            console.log("优秀");
        } else if (Math.floor(score / 10) == 8) {
            console.log("良好");
        } else if (Math.floor(score / 10) == 7) {
            console.log("中等");
        } else if (Math.floor(score / 10) == 6) {
            console.log("及格 ");
        } else {
            console.log("不及格 ");
        }

        switch (Math.floor(score / 10)) {
            case 10:
            case 9:
                console.log("switch --优秀");
                break;
            case 8:
                console.log("switch --良好");
                break;
            case 7:
                console.log("switch --中等");
                break;
            case 6:
                console.log("switch --及格");
                break;
            case 5:
            case 4:
            case 3:
            case 2:
            case 1:
            case 0:
                console.log("switch --不及格");
                break;
            default:
             console.log("异常数据");

        
        }


















    </script>
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